1. Technical Field
The present invention relates, in general, to a multi-layered interconnect structure, and in particular, to the lamination of liquid crystal polymer (LCP) dielectric layers within the multi-layered interconnect structure.
2. Related Art
Organic substrates, such as chip carriers, have been and continue to be developed for many applications. However, it would be desirable to reduce costs and inefficiencies that currently characterize fabrication of organic substrates.
In first embodiments, the present invention provides a multi-layered interconnect structure, comprising:
a thermally conductive layer including first and second opposing surfaces;
a first liquid crystal polymer (LCP) dielectric layer directly bonded to the first opposing surface of the thermally conductive layer with no extrinsic adhesive material bonding the first LCP dielectric layer to the thermally conductive layer;
a second LCP dielectric layer directly bonded to the second opposing surface of the thermally conductive layer with no extrinsic adhesive material bonding the second LCP dielectric layer to the thermally conductive layer;
a first electrically conductive layer within the first LCP dielectric layer; and
a second electrically conductive layer within the first LCP dielectric layer and positioned between the first electrically conductive layer and the thermally conductive layer, wherein the second electrically conductive layer comprises a first plurality of shielded signal conductors.
In second embodiments, the present invention provides a method of making a multi-layered interconnect structure, comprising:
providing a thermally conductive layer including first and second opposing surfaces;
positioning a first liquid crystal polymer (LCP) dielectric layer on the first opposing surface of the thermally conductive layer, wherein the first LCP dielectric layer comprises a first LCP dielectric material, and wherein the first LCP dielectric layer includes a first LCP dielectric sublayer positioned on the first opposing surface of the thermally conductive layer, a first plurality of shielded signal conductors positioned on the first LCP dielectric sublayer, a second LCP dielectric sublayer positioned on the first plurality of shielded signal conductors, a first electrically conductive layer positioned on the second LCP dielectric sublayer, and a third LCP dielectric sublayer positioned on the first electrically conductive layer; and
positioning a second LCP dielectric layer on the second opposing surface of the thermally conductive layer; wherein the second LCP dielectric layer comprises a second LCP dielectric material; and
subjecting the first and second LCP dielectric layers to a first and second temperature that are less than the nematic-to-isotropic transition temperature of the first and second LCP dielectric materials, respectively, for a dwell time and at an elevated pressure that is sufficient to cause the first and second LCP dielectric materials to plastically deform and to cause: bonding of the first LCP dielectric sublayer to the thermally conductive layer without any extrinsic adhesive layer disposed between the first LCP dielectric sublayer and the thermally conductive layer, and bonding of the second LCP dielectric sublayer to the thermally conductive layer without any extrinsic adhesive layer disposed between the second LCP dielectric sublayer and the thermally conductive layer.
In third embodiments, the present invention provides an electrical structure, comprising:
a first 2S1P substructure, comprising a first dielectric layer, a first power plane within the first dielectric layer, a top signal plane on a top surface of the first dielectric layer, a bottom signal plane on a bottom surface of the first dielectric layer, and a first electrically conductive via;
a second 2S1P substructure, comprising a second dielectric layer, a second power plane within the second dielectric layer, a top signal plane on a top surface of the second dielectric layer, a bottom signal plane on a bottom surface of the second dielectric layer, and a second electrically conductive via; and
a joining layer having first and second opposing surfaces and an electrically conductive plug therethrough, wherein the joining layer comprises a liquid crystal polymer (LCP) dielectric material, wherein the first opposing surface of the joining layer is directly bonded to the first dielectric layer of the first 2S1P substructure with no extrinsic adhesive material bonding the joining layer to the first dielectric layer, wherein the second opposing surface of the joining layer is directly bonded to the second dielectric layer of the second 2S1P substructure with no extrinsic adhesive material bonding the joining layer to the second dielectric layer, and wherein the electrically conductive plug electrically couples the first electrically conductive via to the second electrically conductive via.
In fourth embodiments, the present invention provides a method for forming an electrical structure, comprising:
providing a first 2S1P substructure, said first 2S1P substructure comprising a first dielectric layer, a first power plane within the first dielectric layer, a top signal plane on a top surface of the first dielectric layer, a bottom signal plane on a bottom surface of the first dielectric layer, and a first electrically conductive via;
providing a second 2S1P substructure, said second 2S1P substructure comprising a second dielectric layer, a second power plane within the second dielectric layer, a top signal plane on a top surface of the second dielectric layer, a bottom signal plane on a bottom surface of the second dielectric layer, and a second electrically conductive via;
providing a joining layer, said joining layer having first and second opposing surfaces and an electrically conductive plug therethrough, wherein the joining layer comprises a liquid crystal polymer (LCP) dielectric material; and
directly bonding the joining layer to the first dielectric layer of the first 2S1P substructure at the first opposing surface and to the second dielectric layer of the second 2S1P substructure at the second opposing surface, by subjecting the first 2S1P substructure, the joining layer, and the second 2S1P substructure to an elevated temperature, elevated pressure, and dwell time sufficient for effectuating said bonding, wherein the elevated temperature is less than the nematic temperature of the LCP dielectric material during the dwell time, wherein no extrinsic adhesive material is disposed between the joining layer and the first dielectric layer, wherein no extrinsic adhesive material is disposed between the joining layer and the second dielectric layer, and wherein the electrically conductive plug electrically couples the first electrically conductive via to the second electrically conductive via.
The present invention advantageously reduces processing time and processing costs, and reduces dielectric layer thickness, in the fabrication of organic substrates.